The computer has greatly affected essentially all forms of information management, including the graphical editing and computer aided design and drafting (CAD) tools. Some simpler geometric modeling computer program products are two dimensional, providing only length and width dimensions of objects, while more complex and powerful computer program products provide three dimensional editing and visualization.
Today, computer aided manufacturing (CAM) applications work integral with CAD applications to ease the design and production of machined parts. To mill these machined parts, numerically controlled (NC), or computer numerically controlled (CNC) machines cut away material from a block of matter in various stages, commonly referred to as rough finishing and fine finishing where extra stock can also be added or removed.
The concept of extra stock is known in the industry and refers to adding more or removing more material than the design part to account for other variables. For example, after a part is designed on a CAD/CAM system, it is milled with an extra one millimeter of custom stock surrounding the part so that the part can be heat treated to increase a hardening property of the part. Then the final one millimeter is milled in a fine finish operation on the heat treated part. The fine finish operation occurs because it is easier to rough the part from a non-heat treated “softer” blank and leave one millimeter for fine finish milling, treat the part with extra stock, and remove the remaining one millimeter, than it is to heat-treat the blank, and mill the entire designed part from a hardened blank.
Manufacturing engineers commonly apply stock for reasons mentioned above, and they often have to account for tolerance information not included in the part geometry; as a result it is common to partially offset a part boundary surface at the stage of tool path generation. Without proper functionality, NC-programmers have to resort to workarounds lacking part associativity and requiring a lot of extra effort.
There is a need for a solution that can provide a boundary member solution that can intelligently apply tolerance offsets, and fine finish stocking, while associating the boundary solution to the parametrics of the CAD/CAM design.
Except as may be explicitly indicated otherwise, the following definition(s) apply:
blend, n., generic term for both rounds and fillets.
boundary n., a parameterized curve consisting of an ordered set of contiguous linear or arc segments, where segment is also called member.